The present invention relates generally to a device for manually pumping fluid in a sealed fluid system and, more specifically, to a manually operated refrigerant recovery device which pumps refrigerant from a fluid source to a recovery tank under pressure.
Due to environmental concerns, the use of chlorinated fluorocarbons (CFC) in coolants or refrigerants of air conditioning systems is being rapidly phased out. Further, existing air conditioning systems employing CFC refrigerants are subject to increased governmental regulation, one example being that CFC refrigerants must now be recovered rather than released into the atmosphere. As a result, refrigerant recovery devices are increasingly required in the servicing of air conditioning systems employing CFC refrigerants.
Previous refrigerant recovery devices have tended to be complex, and as a result, have been expensive both in initial cost and in recurring costs. For example, Rollins U.S. Pat. No. 5,138,847, although disclosing a refrigerant recovery apparatus which may be used on-site, still entails a somewhat complex and cumbersome system including a motorized pump, a condenser, a fan and both a temporary storage container and a receiving tank. Given the widespread use of CFC refrigerants, the Rollins refrigerant recovery system is too complex and costly to meet the needs of the average repairman. Therefore, a need exists for a refrigerant recovery device which is simple, inexpensive and adaptable to a variety of air conditioning systems.
Several hand-operated lubricant injection pumps are known that are used with refrigeration systems. These pumps are used to inject lubricant at atmospheric pressure into a pressurized compressor unit to replenish the oil in the crankcase of the compressor unit. Examples of these devices are shown in U.S. Pat. No. 4,698,983 to Hechavarria, U.S. Pat. No. 4,467,620 to Bradley et al. and U.S. Pat. No. 5,027,605 to Hardesty. One of the benefits of such a manual pump, for example, is the relative ease with which the average mechanic may inject additional lubricants into the air conditioning system of an automobile. However, these devices are not intended for use in a sealed fluid system to transfer fluids from a pressurized source to a pressurized recovery tank.
Therefore, a need exists for an improved refrigerant recovery device. Such a device should be simple, inexpensive and adaptable to a variety of refrigeration systems. Preferably, such a device should be manually operated to reduce its cost and complexity. Ideally, the device resists the corrosive effects common to refrigerants employed in air conditioning systems.